The present invention relates to a magnetic head slider support mechanism used in a magnetic disk storage and a magnetic disk storage having the magnetic head slider support mechanism.
FIG. 36 shows a rotary actuator type positioning mechanism suited for high-speed, high-precision positioning of a magnetic head to a designated track on a disk. Referring to FIG. 36, a magnetic head slider support mechanism (to be referred to as a slider support mechanism hereinafter) 41 pivots in the seek direction indicated by the arrow to position the magnetic head mounted on the distal end of the mechanism. As slider support mechanisms 41, a slider support mechanism, like the one shown in FIGS. 37A and 37B, assembled from a load beam 2 and a flexure 5 which are separately manufactured, and a slider support mechanism, like the one shown in FIGS. 38A and 38B, obtained by integrally forming a load beam 2 and a flexure 5, are known.
In the slider support mechanism shown in FIG. 37A, the flexure 5 has a slider mount stage 7 in the longitudinal direction of the load beam 2, and a slider 1 is bonded to the stage 7. The slider 1 is point-supported by a pivot 6, which is attached to the load beam 2, near the barycentric position. The flexure 5 has a low stiffness and allows the motions of the slider 1 in a rolling direction RX and a pitching direction RY. With this structure, the slider 1 can flexibly turn on the pivot 6. Reference numeral 11 denotes a flange; and 13, a mount.
A wire-integrated type suspension (FIGS. 38A and 38B) suited for an MR head has been developed. This MR head uses a magnetoresistive effect and hence is used as a play-only head. The MR head is used together with a write head (inductive head). In this case, the number of signal lines doubles (four) as compared with a structure using a conventional magnetic head (write/read inductive head). For this reason, the rigidity of a signal line loop may act as a disturbance on a flying system to change the designed flying height of the slider or interference with stable flying unless forming of the signal lines is properly performed.
As the flying height and size of the slider decrease to meet the demand and higher recording densities, the forming design of the signal lines, in combination with a reduction in air bearing stiffness, poses delicate problems. For this reason, wire-integrated type suspensions have recently been developed (Japanese Patent Laid-Open Nos. 3-189976 and 5-234295). According to such a suspension, thin films as signal line patterns are directly formed on a load beam, and the signal line terminals of the magnetic head are directly bonded to the signal line patterns formed on the load beam surface, thereby removing disturbance factors from the flying system, and improving the assembly/working properties of the magnetic head support mechanism to attain a reduction in manufacturing cost.
FIGS. 38A and 38B show a wire-integrated type suspension. FIGS. 38A and 38B shows the upper and lower surfaces of the suspension, respectively. As shown in FIG. 38B, thin films as signal lines 9 are directly formed on a load beam 2. Reference numeral 14 denotes a mount base.
In such a wire-integrated type suspension, since thin films are formed as signal line patterns, the flexure portion of the magnetic head support mechanism inevitably has a flexure-integrated type structure instead of a conventional flexure/load beam assembly structure.
FIGS. 39A and 39B show the flexure portions of the above two types of slider support mechanisms. FIG. 39A shows the flexure portion of the slider support mechanism in FIGS. 37A and 37B, which is assembled from the separately manufactured load beam and flexure. FIG. 39B shows the flexure portion of the wire-integrated type slider support mechanism shown in FIGS. 38A and 38B. The flexure portion of the wire-integrated type suspension in FIG. 38B inevitably has a pivotless structure because the flexure 5 and the load beam 2 are integrally formed.
In the flexure portion having the pivot structure shown in FIG. 39A, the pivot 6 attached to the load beam 2 (or on the flexure side) allows the flexible slider 1 to roll/pitch. In the flexure portion having the pivotless structure shown in FIG. 39B, a pressure load acts on the slider 1 in the form of a surface-distributed load instead of an ideal point load. For this reason, the flying height of the slider 1 deviates from the designed flying height, or elastic deformation of the flexure portion causes a load loss to fail to obtain the designed load. Alternatively, since flexure vibrations are directly transmitted to the flying system (off the center of gravity), flying variations in the resonant frequency band appear after being amplified.
A slider support mechanism with a structure having the advantages of both the flexure portions shown in FIGS. 39A and 39B is disclosed in Japanese Patent Laid-Open No. 6-302043. FIG. 40 shows the structure of this mechanism. The same reference numerals in FIG. 40 denote the same parts as in FIG. 37. A beam portion 401 integrally formed with a load beam 2 is formed in the central portion of a flexure 5. A pivot 6 is formed in substantially the central portion of the beam portion 401. The pivot 6 has a spherical shape to be engaged with a convex opposing portion of a core (magnetic field generating means) 402, and hence is in point-contact with the core 402. With this structure, the core 402 can freely turn on the pivot 6.
The pivot of the flexure portion disclosed in Japanese Patent Laid-Open No. 6-302043 is formed by bulging using a mold. The slider support mechanism is mainly made of stainless steel. Since stainless steel exhibits noticeable work-hardening and great springback, when the pivot 6 is to be formed by bulging, a crease prevention region must be ensured around the pivot to prevent a crease, as shown in FIG. 41.
When a spherical pivot 6a shown in FIG. 42A is to be formed, a crease prevention region having an area about twice the molding area is required. To form a pivot used for a 50% slider suspension, therefore, a working region (crease prevention region) having a size of about 0.336 mm to 0.6 mm, which is about twice the diameter (0.168 mm to 0.3 mm) of the pivot, must be ensured. For this reason, it is difficult to reduce the size of the slider support mechanism, and especially the flexure portion.
When this technique is to be applied to a wire-integrated type suspension, in particular, wiring patterns must be formed avoiding the pivot portion and the crease prevention region. That is, the degree of freedom in wiring design is low.
In addition, to form a low-profile load beam, the height of a pivot must be decreased. If, however, the height of the pivot 6 is decreased, it is difficult to form a spherical pivot portion by molding. As shown in FIG. 42B, therefore, a low-profile pivot or flat pivot 6b is formed. As a result, the contact area with the slider 1 increases.
As the contact area with the slider 1 increases, an off-track error is caused for the following reason. When the magnetic head is sought over a recording medium 42, the slider 1 separates from the pivot 6 and is then moved greatly, resulting in a positional offset (slipstick). In this state, when the seeking operation is complete, the slider 1 comes into contact with the pivot 6 and keeps supporting it.